Table 2.

Instruments and Tests Used in Reviewed Studies Categorized by Performance Outcome.

Performance outcome	Instruments/tests used
Subjective (self-reported) sleepiness	Karolinska sleepiness scale, Stanford Sleepiness Scale, VAS for sleepiness, pictorial sleepiness scale
Objective sleepiness	Repeated test of sustained wakefulness, EOG for rolling eye movements, videotapes of  behavioral alertness, sleep latency test
Reaction time and vigilance, cognitive  functioning	PVT-192 metrics: fastest 10% of responses, slowest 10% of responses, lapses, mean and median  reaction times; visual vigilance task; critical flicker fusion frequency; 3-choice reaction time  test; 2-choice visual reaction time test; Mackworth clock vigilance task; simple reaction time  task; choice reaction time test; symbol-digit substitution task; letter cancellation task
Subjective fatigue	VAS; Profile of Mood States, Fatigue and Vigor subscales; Fatigue Feeling scale
Logical reasoning performance	Logical reasoning performance test, logical reasoning test
Work task and driving	Typing words into documents, mental arithmetic, driving simulator, catheter insertion simulation
Workload	NASA Task Load Index (mental, physical, temporal demands, performance effort, frustration)
Memory recall	Probed memory recall test

Note. EOG = electrooculogram; PVT = psychomotor vigilance task; VAS = visual analog scale.